There's currently no tests to verify wbt is working properly, this patch
fixes that. Simply run a varied workload and measure the read latencies
with wbt off, and then turn it on and verify that the read latencies go
down.
Signed-off-by: Josef Bacik <jo...@toxicpanda.com>
---
common/fio | 8 +++++
common/rc | 8 +++++
tests/block/022 | 94 +++++++++++++++++++++++++++++++++++++++++++++++++++++
tests/block/022.out | 2 ++
tests/block/026 | 12 ++-----
5 files changed, 114 insertions(+), 10 deletions(-)
create mode 100755 tests/block/022
create mode 100644 tests/block/022.out
diff --git a/common/fio b/common/fio
index e407088840b8..9e1a0557ac61 100644
--- a/common/fio
+++ b/common/fio
@@ -192,3 +192,11 @@ _fio_perf_report() {
TEST_RUN["$FIO_PERF_PREFIX$name"]="$value"
done
}
+
+_fio_results_key() {
+ local job=$1
+ local key=$2
+ local resultfile=$3
+
+ jq '.jobs[] | select(.jobname == "'"$job"'") | .'"$key" "$resultfile"
+}
diff --git a/common/rc b/common/rc
index 153a32358519..91972d7b0130 100644
--- a/common/rc
+++ b/common/rc
@@ -183,6 +183,14 @@ _test_dev_is_pci() {
return 0
}
+_test_dev_supports_wbt() {
+ if [[ ! -e "${TEST_DEV_SYSFS}/queue/wbt_lat_usec" ]]; then
+ SKIP_REASON="$TEST_DEV does not support wbt"
+ return 1
+ fi
+ return 0
+}
+
_get_pci_dev_from_blkdev() {
readlink -f "$TEST_DEV_SYSFS/device" | \
grep -Eo '[0-9a-f]{4,5}:[0-9a-f]{2}:[0-9a-f]{2}\.[0-9a-f]' | \
diff --git a/tests/block/022 b/tests/block/022
new file mode 100755
index 000000000000..647f759e4cd0
--- /dev/null
+++ b/tests/block/022
@@ -0,0 +1,94 @@
+#!/bin/bash
+# SPDX-License-Identifier: GPL-3.0+
+# Copyright (C) 2018 Josef Bacik
+#
+# A basic test to exercise wbt and verify it's working.
+
+. tests/block/rc
+
+DESCRIPTION="run a read workload and write workload together with wbt"
+
+requires() {
+ _have_fio && _have_program jq
+}
+
+device_requires() {
+ _test_dev_supports_wbt
+}
+
+test_device() {
+ echo "Running ${TEST_NAME}"
+
+ fio_config="$TMPDIR/test.fio"
+ fio_results="$TMPDIR/results.json"
+ fio_args=("--output-format=json" "--output=$fio_results")
+
+ cat << EOF > "$fio_config"
+ [global]
+ group_reporting
+ numjobs=8
+ filename=$TEST_DEV
+ randseed=12345
+ runtime=30
+ ioengine=psync
+
+ [reads]
+ new_group
+ readwrite=randread
+
+ [writes]
+ new_group
+ readwrite=randwrite
+EOF
+
+ local wbt_setting
+ wbt_setting=$(_test_dev_queue_get wbt_lat_usec)
+
+ _test_dev_queue_set wbt_lat_usec 0
+
+ # Run just the reads to get a baseline read latency for this workload
+ if ! fio "${fio_args[@]}" "$fio_config"; then
+ echo "fio exited with status $?"
+ return 1
+ fi
+
+ local avg_lat
+ avg_lat=$(_fio_results_key reads read.lat_ns.mean "$fio_results")
+ avg_lat=$(echo "$avg_lat" | cut -d . -f 1)
+
+ echo "avg latency $avg_lat" >> "$FULL"
+
+ # WBT isn't immediate, it requires missing latency targets before it
+ # starts to clamp down on writes, so give ourselves a little wiggle room
+ # to make sure our read latencies are still protected.
+ local thresh=$((avg_lat - avg_lat * 15 / 100))
+
+ echo "threshold is $thresh" >> "$FULL"
+
+ # Fast enough disk means we may not throttle writes, so set the
+ # threshold to something stupid low so we can verify wbt is doing
+ # something. Otherwise the defaults will be fine for spinning rust.
+ if [[ $(_test_dev_queue_get rotational) -eq "0" ]]; then
+ _test_dev_queue_set wbt_lat_usec 1
+ else
+ _test_dev_queue_set wbt_lat_usec "$wbt_setting"
+ fi
+
+ if ! fio "${fio_args[@]}" "$fio_config"; then
+ echo "fio exited with status $?"
+ return 1
+ fi
+ _test_dev_queue_set wbt_lat_usec "$wbt_setting"
+
+ avg_lat=$(_fio_results_key reads read.lat_ns.mean "$fio_results")
+ avg_lat=$(echo "$avg_lat" | cut -d . -f 1)
+ echo "avg latency contended is $avg_lat" >> "$FULL"
+
+ # Verify we are at least somewhat protected now
+ if [[ $avg_lat -gt $thresh ]]; then
+ echo "Read latency too high, wbt not working?"
+ return 1
+ fi
+
+ echo "Test complete"
+}
diff --git a/tests/block/022.out b/tests/block/022.out
new file mode 100644
index 000000000000..14d43cb1c828
--- /dev/null
+++ b/tests/block/022.out
@@ -0,0 +1,2 @@
+Running block/022
+Test complete
diff --git a/tests/block/026 b/tests/block/026
index 88113a99bd28..8b18e6314d5e 100644
--- a/tests/block/026
+++ b/tests/block/026
@@ -14,21 +14,13 @@ requires() {
_have_program jq
}
-fio_results_key() {
- local job=$1
- local key=$2
- local resultfile=$3
-
- jq '.jobs[] | select(.jobname == "'"$job"'") | .'"$key" "$resultfile"
-}
-
sum_read_write_bytes() {
local job=$1
local resultfile=$2
local readbytes writebytes
- readbytes=$(fio_results_key "$job" read.io_bytes "$resultfile")
- writebytes=$(fio_results_key "$job" write.io_bytes "$resultfile")
+ readbytes=$(_fio_results_key "$job" read.io_bytes "$resultfile")
+ writebytes=$(_fio_results_key "$job" write.io_bytes "$resultfile")
echo $((readbytes + writebytes))
}
--
2.14.3
